Storage Chapter 8, Lecture 3 “So, despite the brain’s vast storage capacity, we do not store information as libraries store their books, in discrete, precise locations.” - David Myers

Storage: Retaining Information Storage is at the heart of memory. Three stores of memory are shown below: Sensory Memory Working Memory Long-term Memory Encoding RetrievalEncoding Events Retrieval

Sensory Memory Sensory Memory Working Memory Long-term Memory Encoding RetrievalEncoding Events Retrieval

Whole Report The exposure time for the stimulus is so small that items cannot be rehearsed. R G T F M Q L Z S 50 ms (1/20 second) “Recall” R T M Z (44% recall) Sperling (1960)

Partial Report Low Tone Medium Tone High Tone “Recall” J R S (100% recall) Sperling (1960) argued that sensory memory capacity was larger than what was originally thought. 50 ms (1/20 second) S X T J R S P K Y

Time Delay “Recall” N _ _ (33% recall) Time Delay 50 ms (1/20 second) A D I N L V O G H Low Tone Medium Tone High Tone

Sensory Memory The longer the delay, the greater the memory loss Percent Recognized Time (Seconds)

Sensory Memories Iconic 0.5 sec. long Echoic 3-4 sec. long Hepatic < 1 sec. long The duration of sensory memory varies for the different senses.

Working Memory Sensory Memory Working Memory Long-term Memory Encoding RetrievalEncoding Events Retrieval

Working Memory Working memory, the new name for short-term memory, has a limited capacity (7±2) and a short duration (20 seconds). Sir George Hamilton observed that he could accurately remember up to 7 beans thrown on the floor. If there were more beans, he guessed.

Capacity You should be able to recall 7±2 letters. The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information (1956). George Miller M U T G I K T L R S Y P Ready?

Chunking F-B-I-T-W-A-C-I-A-I-B-M The capacity of the working memory may be increased by “chunking.” FBI TWA CIA IBM 4 chunks

Duration Peterson and Peterson (1959) measured the duration of working memory by manipulating rehearsal. CH?? The duration of the working memory is about 20 sec. CHJ MKT HIJ …

Working Memory Duration

Long-Term Memory Sensory Memory Working Memory Long-term Memory Encoding RetrievalEncoding Events Retrieval

Long-Term Memory Essentially unlimited capacity store. The Clark’s nutcracker can locate 6,000 caches of buried pine seeds during winter and spring. R.J. Erwin/ Photo Researchers

Memory Feats

Memory Stores Feature Sensory Memory Working Memory LTM EncodingCopyPhonemicSemantic CapacityUnlimited7±2 ChunksVery Large Duration0.25 sec.20 sec.Years

Storing Memories in the Brain 1.Loftus and Loftus (1980) reviewed previous research data showing, through brain stimulation, that memories were etched into the brain and found that only a handful of brain stimulated patients reported flashbacks. 2.Using rats, Lashley (1950) suggested that even after removing parts of the brain, the animals retain partial memory of the maze.

Synaptic Changes In Aplysia, Kandel and Schwartz (1982) showed that serotonin release from neurons increased after conditioning. Photo: Scientific American

Synaptic Changes Long-Term Potentiation (LTP) refers to synaptic enhancement after learning (Lynch, 2002). An increase in neurotransmitter release or receptors on the receiving neuron indicates strengthening of synapses. Both Photos: From N. Toni et al., Nature, 402, Nov Courtesy of Dominique Muller

Stress Hormones & Memory Heightened emotions (stress-related or otherwise) make for stronger memories. Flashbulb memories are clear memories of emotionally significant moments or events Scott Barbour/ Getty Images

Beryl Benderly has described “flashbulb” memories this way: “It’s as if our nervous system takes a multimedia snapshot of the sounds, sights, smells, weather, emotional climate, even the body postures we experience at certain moments.” In a sentence or two, write down your three most vivid memories…

A car accident you were in or witnessed(85) When you first met your college roommate(82) Your high school graduation(81) Your senior prom(78) An early romantic experience(77) A time you had to speak in front of an audience(72) When you got your admissions letter from college(65) The day President Reagan was shot in Washington(52) Your first flight(40) The moment you opened your SAT scores(33) Your seventeenth birthday(30) The last time you ate a holiday dinner at home(23) Your first college class(21) The first time your parents left you alone at home(19) Your thirteenth birthday(12) The percentage of Duke students who had flashbulb recollections of each event:

Storing Implicit & Explicit Memories Explicit Memory refers to facts and experiences that one can consciously know and declare. Implicit memory involves learning an action while the individual does not know or declare what she knows. p. 343

Hippocampus Hippocampus – a neural center in the limbic system that processes explicit memories. Weidenfield & Nicolson archives

No New Memories Anterograde Amnesia Anterograde Amnesia (HM) Surgery After losing his hippocampus in surgery, patient Henry M. (HM) remembered everything before the operation but cannot make new memories. We call this anterograde amnesia. Memory Intact Different from retrograde amnesia, which is loss of memory from before an event or injury.

Implicit Memory HM learned the Tower of Hanoi (game) after his surgery. Each time he plays it, he is unable to remember the fact that he has already played the game. HM is unable to make new memories that are declarative (explicit), but he can form new memories that are procedural (implicit). C B A

Cerebellum Cerebellum – a neural center in the hindbrain that processes implicit memories.

Homework Read p “At any given moment, we can consciously process only a very limited amount of information.” - David Myers